What be the correct number of cards in the Full Speed Ahead and Action Stations decks?

I appreciate that it will have to be at least 6 of each per ship but presume that, for randomness, more cards should be included in the decks otherwise it will be obvious what cards have been discarded and then picked up by the next player.

The Rulebook describes the contents of each deck, and when playing I have one deck to hand for each side - so that no player can block out the rarer cards simply by holding them and to have enough cards for each side. With six ships maximum and often only 3 a side to start worrying about I don't see running low as an issue normally and with reshuffling of decks once the deck is depleted things run happily along in my experience.